1. Field of the Invention
The present invention relates to an exhaust gas purification device in an internal combustion engine, and more particularly to an exhaust gas purification device for purifying unburned components adsorbed by an adsorbent, and a method thereof.
2. Description of the Related Art
An exhaust gas purification device, which adsorbs unburned components of such exhaust gas as hydrocarbon (HC) by an adsorbent installed in a bypass passage until an exhaust gas purification catalyst is activated after the cold start of an internal combustion engine, for example, and desorbs the unburned components after warming up completes, and purifies the desorbed components using an exhaust gas purification catalyst (three-way catalyst) disposed downstream of the adsorbent, has been proposed. This exhaust gas purification catalyst has an oxygen storage function to store oxygen. In the exhaust gas purification device, an amount of oxygen required to purify the desorbed unburned components must be supplied to the exhaust gas purification catalyst.
Japanese Patent Application Publication No. 6-93840 (JP-A-6-93840) discloses an exhaust gas purification device wherein secondary air introduction means, such as an air injection device, is installed in an exhaust passage in order to supply oxygen to an exhaust gas purification catalyst.
In JP-A-6-93840, however, a secondary air supply device, that is, an additional device, must be provided.